This invention relates to a method for determining finish level on a moving synthetic polymeric material, more particularly, it relates to determining such finish levels on filaments by monitoring electrostatic voltage(s) (ESV) on filaments gathered into a tow.
Substances known as finishes are usually applied to synthetic polymeric filaments for lubrication to reduce friction as they advance over guides, draw pins and other machine elements in various filament handling processes. Finishes may also be applied to reduce the generation of static electricity, conduct such charges away, or provide soil or stain resistance capability to the yarn.
If the supply or application of finish is interrupted, increased or reduced, the filament handling process may break down or the product may be unsatisfactory to the customer. Since finishes are usually colorless, the absence of finish even on the outside of a filament package is difficult to detect, and a temporary finish interruption is usually not detected.
Methods for detecting the presence or absence of finish are known, employing instruments which respond to some characteristic of the finish such as conductance. However, such devices are often quite expensive, difficult to maintain and are usually not applicable to on-line real time finish monitoring.